1. Field of the Invention
This invention relates to a turntable having multiple-point touch function for a digital sound-signal device, particularly to one having a touch-control turntable divided into a plurality of memory regions. When a user's hand touches different locations on the touch-control turntable, the digital sound-signal device can output different sound signals or make sound effects of SCRATCH, and when the user slides the touch-control turntable upward and downward or leftward and rightward, action of skipping and picking out songs can be done. Further, the speed of sound signal broadcasting can be lowered or retrieved by the magnitude of force that a user touches the turntable.
2. Description of the Prior Art
Generally, on a sound-signal specialized occasion, a DJ likes to output different sound effects by scratching a record on a traditional record tray. (For instance, a DJ can quickly and precisely control a record to rotate clockwise or counterclockwise to make sound effects with hands at a specified region of the record. At present, a CD player is operated to read a CD by laser light and the CD is only rotated clockwise perpetually at fixed lines and speeds in the course of broadcasting, thus impossible to create different sound effects; therefore, a DJ sill likes to perform by means of traditional record tray. However, one traditional record can be cut thereon with only a few songs so a DJ has to carry a large box of records with him in order to carry out performance, taking a lot of exertion and causing much inconvenience. When a DJ scratches a record, the record tray is rotated constantly, and a record pad made of felt is provided between the record and the record tray for separating them; therefore, when the record is pressed by hand, the record will stop rotating but the record tray will continue to rotate. When actuated to move forward and backward by the hand of a DJ, the record will move together with the DJ's hand in the same direction, but when the DJ's hand are released from the record, the record will immediately rotate together with the turntable in a same direction.
According to foresaid point of discussion, if a CD is to be used to simulate a traditional record tray, a turntable is necessary to be used for simulating the action of a record tray so that a DJ can operate the turntable to perform an action like scratching a record. When a DJ manually operates a turntable to rotate clockwise and counterclockwise, the rotation of the turntable can be detected by phase difference of a precise photo-sensor, and sound signals can be broadcast normally and reversely by employing a digital signal processor to control a dynamic memory. To enable a CD to function like a traditional record tray on which a record can be touched by hand to stop rotating or released to start rotating together with the record tray and broadcasting instantly, a turntable made of conducting material is employed to let a human body induce the whole plane surface of the turntable with a single-point contact mode for producing different sound signals when the turntable is touched and released. However, a turntable with a single-point contact function can produce only one sound signal and further, when the turntable is touched by hand, music will be immediately stopped broadcasting, unable to simulate a traditional record tray because there is a record pad positioned between the record and the record tray; therefore, when the record tray is rotated and the record is slightly touched, a frictional force between the record and the record pad will be produced to lower the rotating speed of the record but not completely stop the record. Substantially, there must be lots of different sound-signal points on a record so that a variety of sound effects can be made when a DJ scratches the record. The conventional turntable with single-point contact mentioned above cannot store multiple sound signals, nor can it decide to lower or retrieve sound-signal broadcasting speeds by manual force imposed on the turntable.